The invention relates to a new and improved system for visualizing one or more relatively still or animated images to one or more viewers in motion, especially for displaying traffic information or advertisements to the passengers on a train traveling in a subway tunnel.
The conventional principle of generating an animation is known. When a sequence of slightly different images are displayed rapidly one after another, a viewer perceives an animation. In a movie theater, the viewer sits still and the film frames move.
When a viewer is traveling by public transport, such as by train, the near view outside of the windows of the vehicle turns into a blur for the viewer because of the relative movement between the scene and the viewer. In order to display a sharp animated image in synchronism with a viewer in motion, a number of apparatuses and methods have been invented. Prior art includes a sequence of individual image frames mounted beside railway tracks, and a sequence of still images fixed or projected on the corresponding frames. The said still images differ slightly in sequence, such that when a viewer passes by the still images one after another, he perceives an animated image. This principle of creating an animation is just the inverse of the principle of conventional movies: the images are still but the viewer moves. Such prior art is represented by U.S. Pat. Nos. 742,632; 978,854; 2,913,954; 3,653,753; 3,694,062; 5,108,171; 6,016,183; 6,564,486 B1, etc.
However, the aforementioned prior art has the following limitations in application:
According to most of the prior art, when the image frames are set up, the interval between two adjacent frames must be predetermined with respect to a constant speed. If a vehicle speed is too slow compared to the constant speed, a viewer on the vehicle can only see a series of individual still images without animation effect. If a vehicle speed is too fast, the images turn into a blur to the viewer. In practice, when a train is slowing down to stop at or speeding up to leave from a train station, its speed is slow and not constant. In this situation, the known prior art cannot generate a continuous animation from a sequence of still images to the viewers on a moving train, although the sites in the neighborhood of train stations are crucial for displaying the traffic information and advertisements. Moreover, for most of the prior art, the still images are fixed on the frames, so it costs a lot of work and money to renew the images.